Maths/Physics help

[lolo]

i have another question plz:

there were 1240 tickets sold for a concert. Of these, 780 were sold at $24.50 each, while the remainder were sold at a reduction of 20%. Find the total money taken in ticket sales.

thanks

[astarmathsandphysics]

i have another question plz:

there were 1240 tickets sold for a concert. Of these, 780 were sold at $24.50 each, while the remainder were sold at a reduction of 20%. Find the total money taken in ticket sales.

thanks

(780x24.5)+ 0.8x(1240-780)x24.5=28136

[lolo]

thanks .. bt i reli dnt get what u did  .. cn u plz explain
thanks

[astarmathsandphysics]

780 sold at 24.50 so revenue =780x24.5=19110

The remainder have a discount of 20% iethey cost 24.50x0.8=19.60. There are 1240-780=460 of these so revenue =19.60x460=9016

Total revenue =19110+9016=28126

[omarsubei]

Please help me with this question and explain to me why the answer is what it is:

A force of magnitude F1 accelerates a body of mass m from rest to a speed v. A force of
magnitude F2 accelerates a body of mass 2m from rest to a speed 2v.
The ratio: (work done by F2)/(work done by F1) is:

A. 2.
B. 4.
C. 8.
D. 16.

Thanks

[astarmathsandphysics]

Please help me with this question and explain to me why the answer is what it is:

A force of magnitude F1 accelerates a body of mass m from rest to a speed v. A force of
magnitude F2 accelerates a body of mass 2m from rest to a speed 2v.
The ratio: (work done by F2)/(work done by F1) is:

A. 2.
B. 4.
C. 8.
D. 16.

Thanks
The accelerations are eqaul sinceF2/2m=F1/m therefore from v^2=u^"+2as, s=v^2/2a sobody 2 travels 4 times as far as body 1.
(work done by F2)/(work done by F1)=F2*4s/F1*s=4

[astarmathsandphysics]

One question about Statistics

The height of certain plants are normally distributed. The plants are classified into three categories.

The shortest 12,92% are in cat a
The tallest 10,38% are in cat C
All other plants are in between r and t cm and are cat B

Given that the mean height is 6.84 cm and the standard deviation is 0.25 find t and r

PS> With explanations if possible, i m not an expert on statistics

I had this question a couple of days ago from one of my sudents.

For 12.92 % z=-1.13 so -1.13=(r-6.84)/025 so r=0.25*-1.13+6.84=6.5575
For10.38 we must do 1-.1038=0.8962 and z=1.26 s0 1.26=(t-6.84)/0.25 so t=1.26*0.25+6.84=7.155

[omarsubei]

Please help me with this question and explain to me why the answer is what it is:

A force of magnitude F1 accelerates a body of mass m from rest to a speed v. A force of
magnitude F2 accelerates a body of mass 2m from rest to a speed 2v.
The ratio: (work done by F2)/(work done by F1) is:

A. 2.
B. 4.
C. 8.
D. 16.

Thanks
The accelerations are eqaul sinceF2/2m=F1/m therefore from v^2=u^"+2as, s=v^2/2a sobody 2 travels 4 times as far as body 1.
(work done by F2)/(work done by F1)=F2*4s/F1*s=4

That's the answer I came up with, but strangely the mark scheme says the answer is C (. I was thinking maybe because it's asking about the "Work" done by F, and that there is distance involved (W=Fd), that the distance in F2 is double that of F1 because it's twice as fast?

[astarmathsandphysics]

Can you copy and pasty the question

[omarsubei]

I've attached it as a word document. Thank you.

[astarmathsandphysics]

Please help me with this question and explain to me why the answer is what it is:

A force of magnitude F1 accelerates a body of mass m from rest to a speed v. A force of
magnitude F2 accelerates a body of mass 2m from rest to a speed 2v.
The ratio: (work done by F2)/(work done by F1) is:

A. 2.
B. 4.
C. 8.
D. 16.

Thanks
The accelerations are eqaul sinceF2/2m=F1/m therefore from v^2=u^"+2as, s=v^2/2a sobody 2 travels 4 times as far as body 1.
(work done by F2)/(work done by F1)=F2*4s/F1*s=4

That's the answer I came up with, but strangely the mark scheme says the answer is C (. I was thinking maybe because it's asking about the "Work" done by F, and that there is distance involved (W=Fd), that the distance in F2 is double that of F1 because it's twice as fast?

0.5(2M)V^2/0.mvv^"=8 THEquestion is badlty worded

[omarsubei]

Sorry I don't understand. Could you please explain.

[astarmathsandphysics]

f2 is not twicw F1

[astarmathsandphysics]

u hve to work out the ratiof2/f1 first.

[omarsubei]

You're making me feel even more confused.
The ratio of F2/F1 is 4. How does the "work"  make that 8?